History Byte – Sulphuring: A Stinky Business

Powdered Sulphur

When I think of sulphur, it immediately brings to mind the smell of rotten eggs and childhood trips to the stinky hot springs in Florida. For Victorians, sulphur was thought of as a cleaning and preservative agent. In the realm of brewing, sulphur was used in the brewery and out in the fields. Hops plants were treated with sulphur during the growing season to ward off mould and blight. Powdered sulphur was thrown across the hops fields before the flowers began to form on the hop vine. Once picked, the hops flowers began to brown unless they were sulphured. Hops flowers dried in kilns burning sulphur turned a pale green and were less susceptible to mould. However, the practice of sulphuring hops was the subject of a raging debate in the 1850s about whether the process damaged the hops and negatively impacted beer brewed with them. Without a doubt, hops that were left in the sulphuring chamber too long would leave that characteristic sulphur taste in beer brewed with them, but even lightly sulphured hops were believed by some to be harmful to the brew and the drinker! Hops producers found the preserved hops much more marketable as they looked fresher. While the debate continued in England, many areas in Germany and Bavaria banned the sale and use of sulphured hops! Sulphuring hops was still a common form of preservation in some areas, notably the Czech Republic, up until the 1980s.

Besides treating hops, sulphuring was used to cleanse and decontaminate barrels and kegs in the brewery. Cleanliness was of great importance in the brewery. Dirty barrels infected fresh beer causing it to sour. Brewers used several different processes to ensure cleanliness and ease of cleaning including pitching and varnishing barrels. Transport barrels, that is barrels that went out to customers full of beer, were often returned with dried beer and yeast remnants in them. To clean them, brewers with steam powered breweries would immediately wash out the returned barrels with boiling water and then cool them with cold water. Barrels would be examined with a candle prior to being refilled with beer to check for mould spots or in the case of pitched barrels, holes in the layer of pitch. Barrels that smelt sour were repeatedly scalded out and damaged barrels were sent to the cooper to be repaired. Some breweries used sulphur, to sanitize the barrels before rinsing them with fresh water. Different brewers had different methods, but the idea was to burn sulphur to produce sulphuric acid which would kill any mould or bacteria present in the barrel. One source describes the process of sulphuring a barrel.

“Pieces of linen are prepared by drawing them through melted sulphur. Small pieces of these are then put upon bent wires, the tap-hole of the barrel is closed, and the burning pieces are introduced through the bung-hole, and allowed to burn in the barrel. The effect of the formed sulphurous acid is principally based upon the influence it exerts upon ferments. Sulphuring can never take the place of pitching, but it is advisable to sulphur barrels which have been already used after they have been washed.”

Larger vessels including brewing vats, could be sterilized by wetting down the walls of the vessels and placing a pan with a few hot coals in it and burning sulphur on the coals. The vessels were then tightly covered and left for a day before being thoroughly rinsed out. Some breweries sterilized their whole operation at once by emptying and wetting all their vessels, and burning a pot of sulphur in the room, taking care to seal all the doors and windows. They would then rinse everything and begin the brewing process.

Check out these historic brewing references available thanks to Google Books!